The questions posed by Eliezer are good but elementary. Since there is an entire class of people--moral philosophers--who have been professionally debating and (arguably) making progress on these issues for centuries, why do we believe that we can make much progress in this forum?
I claim that it is highly unlikely that anyone here has an exceptional insight (because of Bayesianism or whatever) that could cause a rational person to assign appreciable importance to this discussion for the purposes of forming moral beliefs. In other words, if we want to improve our moral beliefs, shouldn't we all just grab a textbook on introductory moral philosophy?
Or is this discussion merely an exercise?